JP3875951B2 - Cooling device for projector - Google Patents

Abstract

A device for cooling a projector includes a plurality of air intakes positioned upstream from a suction fan having an integrated motor. A light source of the projector is disposed between a first air intake and the suction fan so that a first air flow, drawn by the fan through the first air intake, flows around and pulls heat away from the light source. A second air intake is positioned to admit a second air flow, also drawn by the fan, that passes through a duct positioned adjacent an upstream side of the suction fan to direct the second air flow against the fan motor. The second air flow, which has a temperature that is not substantially affected by the light source, cools the fan motor and forms an insulating air layer that protects the fan motor from being damaged by the high temperatures of the first air flow.

Description

[0001]
The present invention relates to a cooling device for a projector, the projector including a light source, a suction fan incorporating a motor, a plurality of air inlets, and a louver, and the light source includes one of the air inlets and the suction fan. It relates to a type that is arranged in between and thus is capable of releasing heat to the air passing through the light source.
The current trend is that the market generally desires small, compact and lightweight products. This also applies to video projectors. However, with such miniaturization of video projectors, for example, it is also desired to reduce noise as much as possible. Preferred is a completely silent operation.
[0002]
Since a video projector should be configurable with only optical and electronic elements, it should theoretically be free of noise. But the reality is somewhat different. This is because one of the main components of the projector is a powerful light source of at least 120 watts. This light source generates a significant amount of heat and, if not removed, can damage the entire device. Therefore, it is necessary to cool or remove heat by, for example, a plurality of fans. However, this type of device consisting of one or more fans creates a noise source, especially if all the components must be made as small as possible. That is, if the fan is very small, it must be driven at a correspondingly high speed to generate a sufficient air flow across the components to be cooled or removed.
[0003]
In current large video projectors this is not a serious problem. This is because in that case, a large, sturdy fan that can effectively remove heat even at low rotational speeds (RPM) can be used. The problem arises when the components must be manufactured as small as possible. This is because in that case a plurality of small fans must be used, which are themselves not configured to tolerate high temperatures. For this reason, if a fan is used to remove heat by sucking hot air from an overheated component such as a light source, the fan itself overheats and the bearing dries (because the bearing lubricant is depleted), It will be damaged after a short service life.
It is therefore an object of the present invention to allow the fan motor to be cooled to a temperature below the allowable temperature during operation of the fan. By doing so, the rotational speed of the fan can be kept as low as possible and noise can be avoided.
[0004]
This object has been achieved in an apparatus of the kind described in the preamble of claim 1. The device according to the invention is thus arranged such that the second air inlet sucks air from the surroundings, so that the air temperature at the air inlet is virtually unaffected by the light source, Connected to a conduit opening upstream of the motor of the fan, and aligned so that the longitudinal axis of the conduit is substantially coincident with the rotational axis of the motor, so that a cooler air flow is achieved. Is surrounded by a heat insulating jacket, and outside the jacket, a hot air stream is exhausted from the projector, and thus even if the temperature of the air stream is higher than the allowable temperature of the motor structure, The motor is cooled during work.
Additional features of the invention are set forth in the following claims.
[0005]
In the following, the invention will be explained in more detail with reference to the drawings.
FIG. 3 shows a light source 1 and a suction fan 2, which sucks air from around the light source 1. This projector part incorporating the device according to the invention extends immediately behind the lens 3 so that the inlet 4 for this part is located in the front and is the same as the lens 3 as seen in FIG. On the side. Air is also sucked into the conduit 5 from the inlet 8 on the lower side of the projector so that the fan motor is free from the high temperature caused by the air sucked from the inlet 4. As shown in FIGS. 4 and 2, a louver 6 is placed in front of the fan 2. This louver has, inter alia, the function of preventing light from being emitted to the surroundings via a fan. In addition, the louver board is arranged at an inclined position so that the vertical flow velocity of the air flow flowing obliquely toward the fan matches the vertical flow velocity of the reverse air flow flowing in from the intake port 8.
[0006]
In this way, the vertical components of the two airflows cancel each other, and the cold air from the intake port 8 flows evenly along both sides of the motor 7 of the fan 2. In the projector, no eddy current is generated on the side close to the outside of the housing, and similarly, hot air from the air inlet 4 is equally distributed to both sides of the motor 7 of the fan 2. This means that the cold layer always flows around the motor.
Since the conduit 5 has a curved portion at one end and additionally has an equal cross section over its entire length, the air flow is constant over the entire conduit and does not generate vortices at the same time. The bend is also important for providing a velocity component in the vertical direction to the air, as described above.
[0007]
The horizontal air flow hits the fan motor 7 and is sucked out along the side surface of the fan motor 7. In order to reliably optimize the suction along the fan motor 7, a gap 9 of about 1 mm to 10 mm, preferably 3.5 mm, is provided between the fan motor and the louver 6.
It is difficult to define the exact relationship between conduit curvature and slanted plate slope required to offset two vertical airflows. By experiment, it is easiest to first determine the slope of the plate that ensures that no light is emitted from the fan, and then experiment with different curvatures to obtain a value for the radius of curvature until the best solution is obtained. It is.
The conduit 5 may be formed as part of the louver 6.
If it is not necessary to provide a light screen, the louver can be omitted. The curvature of the conduit 5 is not critical in that case. The main requirement in that case is only to redirect the air flow from the inlet 8 so that all sides of the fan motor are cooled.
[Brief description of the drawings]
FIG. 1 shows a projector having a device according to the invention.
FIG. 2 is a cross-sectional view of the apparatus cut along the line AA in FIG.
3 is an enlarged view of the cooling component of FIG.
FIG. 4 is a detailed perspective view of the fan.

Claims (5)

A cooling system for a projector, the projector includes a light source (1), the suction fan includes a fan motor (7) (2), the first and second intake ports (4,8), louvers ( 6), and the light source (1) is disposed between the first air inlet (4) and the suction fan (2), so that the light source heats the air (A) passing through the light source. In a form that can be released,
The second air inlet (8) is arranged to suck in air (B) from the surroundings, so that the air temperature at the second air inlet (8) is effectively influenced by the light source (1). Without
The inlet (8) is connected to a conduit opening upstream of the fan motor (7), and the longitudinal axis of the conduit at the opening is substantially coincident with the rotational axis of the fan motor. As a result, the cooler air flow (B) effectively surrounds the fan motor (7) to form a thermal insulation jacket, through which the hotter air flow exits the projector. Thus, the projector cooling device is characterized in that the fan motor can be cooled during operation even if the temperature of the air flow (A) is higher than the allowable temperature of the fan motor structure.   The conduit (5) is incorporated in a louver (6), characterized in that an air stream (A) heated by a light source (1) passes through the louver (6). Cooling system.   Said conduit (5) is bent to one side thereof and in addition has a uniform cross section over its entire length so that the air has an equal velocity over the entire conduit and at the same time does not produce vortices. The cooling device according to claim 1, wherein the cooling device is characterized. Cooling according to any one of claims 1 to 3, characterized by a gap (9) provided between the fan motor (7) and the louver (6) of the suction fan (2). apparatus. 5. Cooling device according to claim 4 , characterized in that the gap (9) has an opening of 1 mm to 10 mm, preferably 3.5 mm.

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